Outline

Objective

The high-resolution biometry of the anterior segment on the background of refractive surgery and the evaluation of potential accommodative lens replacement materials is getting more and more importance. The target of this study is a systematic investigation of the temporary available non- contact methods for the analysis of the corneal thickness (CT) and the anterior chamber depth (ACD).

Methods

Measured were 50 phakic eyes of 27 patients at age between 19 to 59 years concerning CT and ACD with the IOL Master (Zeiss), IOL Master focus (Zeiss), Orbscan (B&L), Pentacam (Oculus) and slit lamp pachymetry by Jaeger (Haag- Streit).

Results

With a probability of error of alpha = 0,05 Pentacam and Orbscan, as well as Master focus and Orbscan do not differ significantly concerning the measured median values for CT (Wilcoxon and Wilcox). The intraindividual variability is for Master focus Â± 2μm, Pentacam Â± 6μm, Orbscan Â± 8μm and Jaeger Â± 10μm. With the above probability of error there are no significant differences concerning the ACD between the methods of Jaeger and Master focus, Jaeger and IOL Master, as well as Pentacam and Master focus. The intraindividual variability is for Master focus Â±5,3 μm, Pentacam Â±14 μm, IOL Master Â±23 μm and Jaeger Â±40 μm. The maximal method depending difference in ACD determination has been 270 μm.

Conclusions

All used methods allow a non contact biometry, but the result depends on the know-how of the examinator and the compliance of the patient. The partial coherence interferometry with the IOL Master focus provides an exact measuring along the optical axis with highest reproducibility but it depends on the compliance of the patient.